3: the central part of the flower head of a typical composite made up of closely packed tubular flowers

4: a thin circular object: asausually disc: a phonograph recordb: a round flat plate coated with a magnetic substance on which data for a computer is storedcusually disc:optical disk: as (1):videodisc(2):cd

5usually disc: one of the concave circular steel tools with sharpened edge making up the working part of a disc harrow or plow; also: an implement employing such tools